Recently, a decrease in the populations of marine toads (Bufo marinus) and whistling frogs (Eleutherodactylus johnstonei and E. gossei) has been noted on the island of Bermuda. In the current study, we investigated whether this decline was related to altered immune functions. During August 1998, a significant proportion (25%) of the toads exhibited deformities. Analysis of soil samples revealed presence of chlorinated pesticides and polychlorinated biphenyls (PCBs). Spleen cells from toads collected from more polluted areas of Bermuda exhibited a decrease in B-cell proliferative response to lipopolysaccharide when compared to the responsiveness of B cells from toads collected from less polluted areas. In contrast, the T-cell responsiveness to mitogens in these two groups was not significantly altered. Histological examination of major parenchymatous organs in marine toads and whistling frogs showed alterations in hepatic and splenic morphology, indicative of exposure to toxicants. Together, the current study suggests that the immune functions of toads from contaminated sites of Bermuda are significantly altered, which may contribute to the decline in their population.
Lisa Michelle Hudson Pélanne. Use of the Immune System to Investigate the Toxicity Induced by Environmental Pollutants in Fish, Amphibian, and Mammalian Species. Master’s Thesis submitted to the Faculty of Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of
Master of Science in Biology. 10 April 2002 (attached)